Process for removing vanadium and other harmful materials from petroleum products



at t a o, t attests g a a th m, '14" r n l m a? 9 9 t t uin it i Em in-L L is Ra -l ii Faiented jag 2g l 2 treatment time will vary according to the temperature of 3,92'5316 the oil. In general, the desired reaction is almost in- PROQESd Milt. REMEEVL G VANAEEUM AR stantaneous at higher temperatures. Even at lower tern- YE-WP. HARMFUL EEAHLTLLIALS FRilP/l PETR- LEUM PRQEUCTS Robert V. lleinze, didl Tndiana lllinois larlrway, Harnnrond, in" and Lloyd ll. l'teyerson, 223i Folwell Sta,

Ne nmwa f' Filed Dec. 5, recs, Ser. No. r3541 5 or. 208-453) The present invention relates to the refining or" petroleum and, in particular, to a process for removing vanadium, nickel, etc., from crude petroleum and fractions produced from crude petroleum.

Crude petroleum contains numerous impurities such as sulfur compounds, phenolic and nitrogenous bodies, metals, and the like, which give the various fractions formed from the crude oil undesirable physical and chemical characteristics. These undesirable characteristics include bad odor, poor color stability in storage, and formation of gummy precipitates in storage. One of the more troublesome defects of certain crude oils is their corrosiveness. This property of the oils is at least partly due to the presence of metals such as vanadium. Vanadium containing ash produced by the combustion of fuel oils, for example, attacks the materials from which furnaces and the like are constructed. The Vanadium content of fuel oil ash varies rrom 0% to about 28% for domestic fuel oils and up to about 80% for South American fuel oils. A high vanadium content in fuel oils also is undesirable because it tends to cause incomplete combustion and the formation of excessive fiy ash. The presence of certain metals in crude petroleum and petroleum fractions also have a harmful effect on the activity of cracking catalysts. In a fluidized bed process, for example, it is important t .at the level of vanadium, nickel, etc., in the feedstock be held as low as possible.

A number of methods have been suggested for removing metallic constituents from crude petroleum and pe troleum fractions. These methods include (1) fluid coking of the fue. oil, (2) electrical precipitation after a combination of heat soaking and naphtha dilution, and (3) treatment of the vanadium with certain phosphorus compounds. in general, these methods have not proven to be entirely satisfactory from a cost standpoint and for other reasons.

The principal obiect of the present invention is to provide an improved method for upgrading petroleum oil products.

A more specific object of the present invention is to provide a method for removing vanadium and other harmful metals from petroleum products.

Still another object is to provide a new use for Waste products formed during steel pickling operations.

Ot" er objects will become apparent to those skilled in the art from the following detailed description of the invention.

In general, the subject invention comprises the discovery that vanadium,nickel, and other metals can be removed from petroleum stocks by contacting such stocks with ferrous sulfate. In a preferred embodiment of the invention the ferous sulfate in either its heptahydrate or rnonohydrate form is obtained from spent pickle liquor which is formed when steel is pickled with sulfuric acid.

The process is carried out by mixin the oil to be treated with a slurry of oil and ferrous sulfate, dry ferous sulf te, acid-wet ferous sulfate, etc. The mixture of oil and ferrous sulfate is heated to a temperature of from slightly above room temperature (85 F.) up to 750 F. or more. As temperature of the mixture is raised, water, S0 S0 H 8 and free sulfur are given ofi from the oil. The

peratures only a few seconds are required to carry out the reaction.

The precise reason why the treatment of oil stocks with ferrous sulfate causes the removal of vanadium and other metals is not known. it is believed, however, that sulfur which is released from the sulfate molecule replaces vana diurn and the other metals which had been combined with the oil. During the treatment the ferous sulfate is converted to magnetite (Fe O At least a portion of the magnetite is further converted to hematite (Pe O Because of the weight of the metals, they come down and can either be taken out magnetically or by centrifuging, filtering, settling, electrical precipitation, sonic vibration, distillation, and the like. Subsequent analysis of the treated oil shows that it is substantially free of vanadium and other harmful metals.

inasmuch as a certain amount of sulfur is added to the oil by the subject process, it often is necessary to refine the product subsequently in the same manner as high sulfur-bearing oils are processed. This fact usually is not a disadvantage, however, because high vanadium oils generally also contain high levels of sulfur.

The following examples are illustrative of the subject invention.

Example I In order to demonstrate the effect of ferrous sulfate on petroleum products, cat cycle stock having a high vanadium content was added to acid-wet FeSO .7l-l O in a beaker. Ten percent (10%) by Weight of FeSO was used based on the weight of the oil. Heat was applied to the beaker and a glass stirring rod was used to maintain an intimate contact between the heptahydrate and the oil. As the temperature of the reaction mixture increased, the sulfate crystals were readily transformed to iron oxides. This transition occurred with almost no sticking of the material to the glass beaker. The oil foamed and boiled vigorously as temperature increased above 200 F. When the heptahydrate crystals were added in small amounts, there was a rapid release of vapor. The oil boiled at a much lower temperature than it would without the addition of the iron salt. site the temperature of the oil had reached 600 F., the mixture was cooled. A subsequent analysis of the oil showed that the fraction had undergone both physical and chemical changes. The treated oil was darker but less viscous than the feed oil. The settlings were black and powdered. G11 further heating of the settlings, oil Vapors were released along with S0, gas. As drying continued S0 was also given off. Continued drying caused the settlings to become a dry, magnetic red powder.

In order to prove that vanadium had been transferred from the petroleum stock to the iron oxide mixtures formed during the process, are spectra were obtained both of the initial ferrous sulfate and of the resulting iron oxide. The spectra of the ferrous sulfate showed no lines that could be identified as being due to vanadium. On the other hand, intense lines that were caused by the presence of vanadium were positively identified in the iron oxide mixture. These results fully establish that vanadium present in the petroleum stock accumulates in the iron oxides as a result of the action between the iron sulfates and the oil products.

Example II In these experiments, varying amounts of acid-wet ferrous sulfate heptahydrate was introduced into petroleum stocks contained in an open stainless steel dish. In one of these experiments, about 450 ml. of cat cycle oil was 3 heated on a hot plate to a temperature of about 518 F. Thereafter, several portions of ferrous sulfate heptahydrate was added to the oil with the following results:

dropped to Added few more grains-sol boiled and 522 F. then rose to 525 F. in 1 minute Added few more grainssol boiled and 523 F. then rose to 529 F. in 1 minute Added few oil-wet grains-sol boiled and 526 'F. then rose to 528 F. in 1 minute Added few oil-wet grains-sol boiled and 520 F. then rose to 532 F. in 1 minute Added few oil-wet grains-sol boiled and 526 F. then rose to 532 F. in 1 minute Added few oil-wet grains-sol boiled and 526 F. then rose to 532 F. in 1 minute Added few oil-wet grains-sol boiled and 522 F. then rose to 532 F. in 1 minute Added about 4 times above grains-sol boiled and dropped to 518 F. then rose to 532 F. in 2 /2 minutes The solution was then allowed to stand overnight after which sufiicient additional cat cycle oil was added to bring the solution up to its original level. Upon heating, the oil began to boil at 400 F.

It is apparent from the above experiment and others that the heptahydrate of ferrous sulfate is converted to the monohydrate at relatively low temperatures and with little difliculty. Depending upon the temperature of the oil stock, the ferrous sulfate is quickly converted to reddish brown oxides of iron which are magnetic. At about the same time the oil stocks begin to boil at temperatures that are lower than the boiling point of the untreated material. At no time was any appreciable amount of coke found in the reaction apparatus at the conclusion of the experiment. Depending on the character of the feedstock to which the ferrous sulfate is added, bright clear fractions of gasoline and kerosene are obtained as well as fuel oil fractions. Even cat cycle oil and heavy fuel stocks give bright gasoline and kerosene fractions.

As was indicated above, various forms of ferrous sulfate can be used in carrying out the process. The reagent can be acid-wet, dry, slurried in the oil, etc. The amount of ferrous sulfate by weight based on the Weight of the oil can vary from about 0.1% up to as much as 25%. Our preferred range is from about .5% to 5% by weight FeSO based on the weight of the oil.

The reaction temperature can vary from about 85 F. up to 750 F. or higher. Our broad temperature range, therefore, would be from about 85 to about 1500 F., with our preferred temperature range of from about 220 F. to about 700 F. Like the temperature, pressure used in carrying out the process can vary from atmospheric up to high pressure cracking conditions.

The ferrous sulfate which is used in the process can consist of spent pickle liquor obtained in pickling steel with sulfuric acid. Ordinarily, much of this material is discarded because present recovery systems are costly and cumbersome. The iron oxides that are produced in the process also are commercially valuable to the steel industry.

When ferrous sulfate is used in the manner described above, it seems to act as a catalyst in the refining process which cracks the petroleums and improves the yield of useful products. Additionally, because of an apparent lyophilic effect, vanadium, nickel, and other harmful metals leave the petroleum stock and concentrate in the dropped to dropped dropped dropped to dropped to dropped to formed iron oxides. These materials can then be easily separated form the oil.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A process for removing vanadium from petroleum oil stocks, for improving the yield of low boiling hydrocarbon fractions, and for converting ferrous sulfate into iron oxide which comprises: adding ferrous sulfate to the petroleum oil stock, agitating the resultant mixture at a temperature of at least about F., and thereafter separating the formed iron oxide from said oil stock, said iron oxide having vanadium combined therewith.

2. A process for removing vanadium from petroleum oil stocks, for improving the yield of low boiling hydrocarbon fractions, and for converting ferrous sulfate into iron oxide which comprises: adding ferrous sulfate in the form of crude pickle liquor salts to the petroleum oil stock, agitating the resultant mixture at a temperature of at least about 85 F., and thereafter separating the formed iron oxide from said oil stock, said iron oxide having vanadium combined therewith.

3. A process for removing vanadium from petroleum oil stocks, for improving the yield of low boiling hydrocarbon fractions, and for converting ferrous sulfate into iron oxide which comprises: adding particles of a compound selected from the group consisting of ferrous sulfate monohydrate and ferrous sulfate heptahydrate to the petroleum oil stock, agitating the resultant mixture at a temperature of at least about 85 F., and thereafter separating the formed iron oxide from said oil stock, said iron oxide having vanadium combined therewith.

'4. A process for removing vanadium from petroleum oil stocks, for improving the yield of low boiling hydrocarbon fractions, and for converting ferrous sulfate into iron oxide which comprises: adding from about 0.1% to about 25% by weight of a particulate compound selected from the group consisting of ferrous sulfate monohydrate and ferrous sulfate heptahydrate to the petroleum oil stock, said percentage by weight being based on the weight of said oil stock, agitating the resultant mixture at a temperature of from about 85 F. to about 1500 F., and thereafter separating the formed iron oxide from said oil stock, said iron oxide having vanadium combined therewith.

5. A process for removing vanadium from petroleum oil stocks, for improving the yield of low boiling hydrocarbon fractions, and for converting ferrous sulfate into iron oxide which comprises: adding from about .5 to about 5% by weight of a particulate compound selected from the group consisting of ferrous sulfate monohydrate and ferrous sulfate heptahydrate to the petroleum oil stock, said percentage by weight being based on the weight of said oil stock, agitating the resultant mixture at a temperature of from about 220 F. to about 700 F., and thereafter separating the formed iron oxide from said oil stock, said iron oxide having vanadium combined therewith.

References Cited in the file of this patent UNTTED STATES PATENTS 1,826,142 Lachman Oct. 6, 1931 1,897,582 Morrell et al Feb. 14, 1933 1,999,112 Scott Apr. 23, 1935 2,013,400 Benedict et al Sept. 3, 1935 

1. A PROCESS OR REMOVING VANADIUM FROM PETROLEUM OIL STOCKS, FOR IMPROVING THE YIELD OFF LOW BOILING HYDROCARBON FRACTIONS, AND FOR CONVERTING FERROUS SULFATE INTO IRON OXIDE WHICH COMPRISES: ADDING FERROUS SULFATE TO THE PETROLEUM OIL STOCK, AGITATING THE RESULTANT MIXTURE AT A TEMPERATURE OF AT LEAST ABOUT 85*F., AND THEREAFTER SEPARATING THE FORMED IRON OXIDE FROM SAID OIL STOCK, SAID IRON OXIDE HAVING VANADIUM COMBINED THEREWITH. 